Your mother is one of the legal heirs and you can enjoy your share and she can enjoy her share.
For partition by boundaries either decide amicably (best recourse) or take help of other elders of the family or panchyaat or court of law..
Although your mother can agitate on any grounds deemed fit by her if the grounds are not reasonable the court shall finally decide and partition the property with boundaries..
IT shall be better to understand the reasons and even aspirations of the aged Lady (Mother) and arrive at some amicable solution..
If pachayat parikhat is valid then your father's legal heirs get share from his share ( as per pachayat parikhat) and if IT is not then your father's share is from his father as per succession rules and all of you (his legal heirs) get share from his share....
Per succession rules applicable in your case share of each legal heir/successor/co-sharer is intact….
You may take possession and enjoy till Lady (Mother) agrees or is alive …………..
After her share shall devolve upon her legal heirs/successors including you, IF she does not dispose IT in her life time…
Preferably try to resolve within walls of family …
Or approach a very able senior LOCAL counsel of unshakable repute and integrity specializing in revenue/succession/civil matters well versed with local revenue codes/rules/laws and having successful track record ….. and worth his/her salt …for partition with boundaries thru court of law..